Study sees link between lithium in water and autism that ‘requires further scrutiny’

Key takeaways:

• A study found a link between increased lithium in drinking water and autism risk.
• The authors said the finding requires further scrutiny.

A study of more than 50,000 children born over a 14-year period in Denmark found that children born to mothers who were exposed to higher levels of lithium in their drinking water were moderately more likely to develop autism.

Writing in JAMA Pediatrics, the authors of the study said the finding “requires further scrutiny” in other epidemiological studies.

The prevalence of autism among children has been increasing amid progress in early detection.

The new study begins by noting that although lithium is a naturally occurring trace element that has mood-stabilizing effects, “maternal therapeutic use of lithium has been associated with adverse birth outcomes.”

“Any drinking water contaminants that may affect the developing human brain deserve intense scrutiny,” Beate Ritz, MD, PhD, professor of neurology at UCLA’s David Geffen School of Medicine and professor of epidemiology and environmental health at the UCLA Fielding School of Public Health, said in a press release.

The study by Ritz and colleagues included 8,842 children with autism and a control group of 43,864 children without autism who were all born in Denmark from 2000 through 2013.

The researchers obtained mothers’ addresses from 9 months before their pregnancy to 9 months after their pregnancy and sampled water from 144 public waterworks in Denmark for natural lithium levels.

According to the findings, every interquartile range increase in estimated maternal exposure to lithium in drinking water was associated with increased odds for autism in offspring (OR, 1.23; 95% CI, 1.17-1.29).

According to an explanation from UCLA, maternal exposure to lithium levels in the second and third quartiles was associated with a 24% to 26% higher risk for autism compared with maternal exposure to lithium levels in the 25th percentile. In the highest quartile, the risk was 46% higher compared with the lowest quartile, UCLA noted.

The authors classified lithium exposure as potentially “a novel environmental risk factor” for autism.

“In the future, anthropogenic sources of lithium in water may become more widespread because of lithium battery use and disposal in landfills with the potential for groundwater contamination,” Ritz said. “The results of our study are based on high-quality Danish data but need to be replicated in other populations and areas of the world.”

In an accompanying editorial, David C. Bellinger, PhD, MSc, a professor of neurology at Harvard Medical School and Boston Children’s Hospital, called the implications of the study “complex.”

“Lithium levels in water, at concentrations that Liew and colleagues found to be associated with a potential increased [autism] risk, have also been linked to health benefits, specifically reductions in rates of hospitalization for psychiatric disorders and suicide,” Bellinger wrote. “If all these of associations are valid, the wisdom of Solomon will be required to develop guidelines for lithium in drinking water that are maximally protective of the entire population.”

He said the authors “cautiously and appropriately” acknowledged that their findings warranted “further scrutiny.”

“Until the basic biology of [autism] is better understood, it will be difficult to distinguish causal from spurious associations,” Bellinger said.

References:

Bellinger DC, et al. JAMA Pediatr. 2023;doi: 10.1001/jamapediatrics.2023.0330.

Liew Z, et al. JAMA Pediatr. 2023;doi:10.1001/jamapediatrics.2023.0346.

Higher lithium levels in drinking water may raise autism risk. https://www.eurekalert.org/news-releases/984290. Published April 3, 2023. Accessed April 10, 2023.